In a new study, a Labrador retriever that was trained to sniff out cancer was able to detect colon cancer nearly as accurately as a colonoscopy. The dog was given breath and stool samples of 306 patients, collected right before they received colonoscopies; 48 patients had recently been diagnosed with bowel cancer, and the other 258 were either suffering from another colorectal ailment or had survived cancer, or were healthy. (More on Time.com:Why You Shouldn’t Snuggle with Your Pooch in Bed)

When smelling breath samples, the dog was at least 95% as accurate at identifying cancer as colonoscopy, and 98% correct when sniffing stool samples, the researchers found. Most impressively, the dog was especially good at spotting early stage cancer, and could discern polyps from malignancies, which colonoscopies can’t do.

“Detection of early-stage cancers is the real holy grail in bowel cancer diagnosis because surgery can cure up to 90% of patients who present with early-stage disease,” Trevor Lockett, a bowel cancer researcher with the Commonwealth Scientific and Industrial Research Organization in Australia, told Bloomberg News.

Although there’s not much hope for the routine use of scent dogs in cancer screening — they’re too expensive, for one thing — the current findings suggest that other noninvasive screening measures could be developed to pick up the same scent. (More on Time.com: 5 New Rules for Good Health)

“This study shows that a specific cancer smell does indeed exist,” the researchers wrote in the study, published today in the medical journal Gut. “These odor materials may become effective tools in screening.”